Vulnerability-Lookup

GHSA-HCGC-HFP6-58V4

Vulnerability from github – Published: 2026-06-25 21:31 – Updated: 2026-06-26 18:33

Details

ML-KEM-1024 x64 AVX2 implicit rejection failure in the Fujisaki-Okamoto transform breaks IND-CCA2 security, allowing decapsulation to deviate from the implicit-rejection behavior required by the standard. The AVX2 constant-time ciphertext comparison used during decapsulation never compared the final 32-byte block of the 1568-byte ML-KEM-1024 ciphertext, so a ciphertext manipulated only in those final bytes would compare as equal and decapsulation returned the real shared secret instead of performing the required implicit rejection.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

6.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-10097"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-327",
      "CWE-697"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T20:17:09Z",
    "severity": "MODERATE"
  },
  "details": "ML-KEM-1024 x64 AVX2 implicit rejection failure in the Fujisaki-Okamoto transform breaks IND-CCA2 security, allowing decapsulation to deviate from the implicit-rejection behavior required by the standard. The AVX2 constant-time ciphertext comparison used during decapsulation never compared the final 32-byte block of the 1568-byte ML-KEM-1024 ciphertext, so a ciphertext manipulated only in those final bytes would compare as equal and decapsulation returned the real shared secret instead of performing the required implicit rejection.",
  "id": "GHSA-hcgc-hfp6-58v4",
  "modified": "2026-06-26T18:33:50Z",
  "published": "2026-06-25T21:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-10097"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wolfSSL/wolfssl/pull/10430"
    },
    {
      "type": "WEB",
      "url": "https://www.wolfssl.com/docs/security-vulnerabilities"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-10097 (GCVE-0-2026-10097)

Vulnerability from cvelistv5 – Published: 2026-06-25 19:59 – Updated: 2026-06-26 16:35

Title

ML-KEM-1024 x64 AVX2 incomplete cipher text comparison enables IND-CCA2 break and static private-key recovery

Summary

wolfSSL's AVX2-optimized ML-KEM implementation (mlkem_cmp_avx2) compares only 1536 of the 1568 ciphertext bytes during the Fujisaki-Okamoto re-encryption check in ML-KEM-1024 decapsulation. Ciphertexts that differ from the expected re-encryption solely in bytes 1536-1567 bypass implicit rejection and are accepted as valid, breaking IND-CCA2 security. An attacker able to submit chosen ciphertexts to a decapsulation oracle that uses a static ML-KEM-1024 key, and to observe whether the genuine shared secret or the implicit-rejection secret was produced, can use this as a plaintext-checking oracle to recover the private key. A proof of concept recovered a full ML-KEM-1024 private key with approximately 98% success using roughly 350 chosen ciphertexts. The flaw is a deterministic logic error and does not rely on timing measurements.

Severity

8.3 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-26 13:51 UTC

CWE

CWE-697 - Incorrect Comparison

Assigner

wolfSSL icscert root Scorecard

References

2 references

URL	Tags
https://github.com/wolfSSL/wolfssl/pull/10430	patch
https://www.wolfssl.com/docs/security-vulnerabilities/

Impacted products

1 product

Vendor	Product	Version
wolfSSL	wolfSSL	Affected: 5.7.0 , ≤ 5.9.1 (semver)

Credits

007bsd (https://github.com/007bsd)

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                "timestamp": "2026-06-26T13:51:27.508789Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-HCGC-HFP6-58V4

CVE-2026-10097 (GCVE-0-2026-10097)

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